To create new research directions and opportunities for new collaborations in Down syndrome research, there is a need to bring together two groups of investigators: (1) those specifically studying human chromosome 21 and Down syndrome and its mouse models, and (2) those studying the cell/molecular biology of specific genes that map to chromosome 21 or specific pathways whose components map to chromosome 21, and those developing/using novel methodologies that might be applicable to Down syndrome research. The first group includes experts on chromosome 21 who have been involved in the mapping, sequencing, and annotation of chromosome 21 and orthologous mouse genomic regions, the identification and expression analysis of chromosome 21 and orthologous mouse genes, the creation and analysis of mouse models of Down syndrome, both segmental trisomies and transgenics, and the definition of the human Down syndrome phenotype. Investigators in the second group are not involved in Down syndrome research and may not even be aware that their work can impact Down syndrome research. They are studying individual genes or family members such as transcription factors, protein modifiers, or cell surface receptors that map to chromosome 21, or pathways/processes such as neurogenesis, cell adhesion, or signal transduction, each of which has several component or modulating genes mapping to chromosome 21. Or they are using large scale approaches to assay protein expression or mathematical modeling for pathway analysis. [unreadable] [unreadable] This application requests funding to cover venue and travel expenses for a workshop to bring together approximately 30 established chromosome 21 Down syndrome investigators with approximately 20 non-Down syndrome but chromosome 21 gene/pathway experts to discuss the biology of chromosome 21-encoded genes and the implications for their overexpression in the Down syndrome phenotype. The meeting will be held for three days in Washington, DC within a time frame of five months after the availability of funding. It is anticipated that this workshop will generate new, testable theories for gene-phenotype correlations in Down syndrome, foster new collaborations, and introduce new researchers with novel expertise to the Down syndrome research field. [unreadable] [unreadable] [unreadable]